Modern material handling systems, such as those in mail order warehouses, supply chain distribution centers, airport luggage systems, and manufacturing facilities, face significant challenges in responding to requests for material storage, transportation, and handling. As material handling systems grow, the challenges of space utilization of system resources, including space, equipment, and manpower, can result in lower throughput, unacceptably long response times, an ever-increasing backlog of unfinished tasks, and, in general, poor system performance. Additionally, expanding or reducing the size or capabilities of many material handling systems requires significant changes to existing infrastructure and equipment. As a result, the cost of incremental changes to capacity or functionality may be prohibitively expensive, limiting the ability of the system to accommodate fluctuations in system throughput.